Research On Dynamic Mechanical Properties And Damage Failure Process Of Limestone Based On SHPB Test

In engineering practice,most of the rock often damage under dynamic loading,so it is particularly important to study the dynamic performance of rock materials under high strain rate.As the pace of building a moderately prosperous society in an all-round way,the western mountains have accelerated in infrastructure,and limestone as a kind of very common rocks in the western mountainous area,It is also a must face the object in the construction of the engineering.So it is necessary to study its dynamic mechanical properties and provide certain theoretical guidance for practical engineering problems.This paper combines the “mountain highway disaster monitoring and blasting vibration effect of intelligent technology research” project,based on the Jc7 high slope blasting projects of guiyang(huaxi)to anshun highway,and choose the typical limestone samples in K86+152~K86+600 section,and study the dynamic characteristics of limestone by SHPB experiment,numerical simulation and theoretical analysis,etc.The main contents are as follows:(1)The basic components of the SHPB device,assumptions and principles are introduced in the paper,by use of the theory of one-dimensional stress wave to deduce the three wave method and two wave method in the test data processing.(2)The mechanical properties of limestone is studied through SHPB experiments under uniaxial impact compression,including the stress-strain characteristics,strain rate effect,energy dissipation and failure mode.(3)The dynamic mechanical properties of limestone under dynamic splitting are studied,including the dynamic tensile strength of the strain rate effect,energy dissipation and failure mode,and verify the validity of the test,analyze the stress wave and strain rate curve.(4)Using the theory of damage of statistical mechanics to set up a statistical damage constitutive model based on Weibull distribution,and give the calculation method of model parameters.To verify the rationality of the model according to the model curves and the test curves have a good consistency.Limestonespecimens is analyzed in the regularity of damage evolution under different strain rate,including the damage value D along with the change of strain,the relatation of Dmax and εmax and Dmax along with the change of strain rate.(5)Using the ANSYS/LS-DYNA software and HJC constitutive model,respectively to simulate the impact compression and dynamic splitting tensile process of limestone,and analyze the spread of stress wave in limestone specimen internal process,the dynamic failure process and the final failure mode.